A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
On the formulas menu at the top of Excel, in the Calculation section, is the Calculation Options drop-down menu set to Automatic, if so, it is very unusual if your workbook is not calculating automatically.
For manual calculation, in that Calculation section, there should be a 'Calculate Now' button or you can press F9 or Shift + F9 to perform a manual calculation on the sheet or full workbook.